Spam filters analyze various criteria gathered from the email to determine whether it is spam or not.

In this article I will help you understand spam filters so you prevent your emails from landing in spam folders.

There are 3 Factors that can affect your email deliverability:

  • Score based on your email marketing process
  • Score based on your subscribers’ behavior
  • The reputation of the sending server IP addresses of your email software

1. Your score with your email marketing process

The spam scoring algorithms of each email client are not public but basically works on the basis of "filters".

Here are some tips to avoid being detected as a spammer by email clients:

  1. Personalize your emails.
  2. Rephrase template content.
  3. Use a real reply-to address.
  4. Be aware of spammy phrases.
  5. Keep the content and subject line short.
  6. Avoid using too many images.
  7. Include an “Unsubscribe” Link.
  8. Miss out obscure fonts.
  9. Keep away from link shortener apps.
  10. You should always send newsletters from your own domain.
  11. Get permission first.
  12. Segment your emails.

Let's go through each one separately.

1. Personalize your emails:

Personalizing your emails increases the engagement of your subscribers with your emails. It improves contact's experience with your brand.

Contrary to mass addressing and many repeated typical starts, a personalized, uniquely written email not only gains the trust of the user but also of the email clients.

Appearing like a human, showing your Name, Company Address, Phone number, even Linkedin profile or a link to your calendar is something that lands your email in a primary inbox.

Hint: Add a default value to the first name, if you have contacts without data of their first name.

2. Rephrase template content:

Sending out an email with default content may be considered as irrelevant content, so send out emails (even for testing) that are similar to your final newsletters’ content.

3. Use a real reply-to address:

Email clients may determine whether or not your reply-to email is a real email address, moreover, did you receive any response so far from your previous emails.

Think though nobody will pay attention to replying to spammers or to an email they don’t care about.

Getting responses is an obvious signal for email providers that your emails are legitimate that people care about.

Hint: Try to avoid using emails like noreply@yourcompany.com as it tells subscribers you are not interested in hearing from them.

4. Be aware of spammy phrases:

In both the subject line and body of an email, there are certain spam-trigger words, phrases, and characters that can cause it to be sent to the junk folder.

One instance may not be enough to cause the email to be filtered, but the more you have throughout your campaign, the greater the risk of landing in junk folders.

5. Keep it Short:

When an email client detects that your contacts aren't reading your emails, they start routing your emails into the junk folders.

Do not use a too long subject line either as they can be misleading.

6. Avoid using too many images:

Keep your image-text ratio low and avoid all one image, as these immediately trigger the spam filter.

Image-only emails are often associated with and are used by spammers to avoid phrase detecting. Some filters are sophisticated enough to detect an image’s content and this is still one of the most weighted spam-score.

Hint: Optimize or even crop your images if needed and never insert an image with a long text.

7. Include an “Unsubscribe” Link:

When you send emails out, include an unsubscribe link and do not be frustrated if someone clicks on it.

You can let them even update their preferences instead of unsubscribing from all of your lists.

8. Don't use obscure fonts:

Stick with fonts that work across platforms, like Arial, Verdana, Georgia, and Times New Roman.

9. Keep away from link shortener apps:

Your website URL will be less recognizable. This triggers the spam filter of email clients and may even disable it, so subscribers won't be redirected to the link.

If you use shortened links, your link clicks will not be trackable in Automizy.

Hint: Use hyperlinks or CTA buttons to redirect your subscribers to your website.

10. Always send newsletters from your own domain:

If you send bulk emails from free domains, you are running the risk of sending your newsletters straight to the junk pile.

We know...It’s perfectly fine to send emails to your friend or colleague from domains like @gmail.com, @yahoo.com, @hotmail.com, etc, but we can be honest … your contacts may not give trust to an email sender who does not even have an own domain.

Undeniably, trust is critical to making any relationship in a meaningful, productive way.

Hint: Use clear and reliable names like “newsletter@”, “info@”, contact@”, or “myname@”.

11. Get permission first:

It’s really good to have a big list, but let Quality be over Quantity.

The best email senders have a permission-based list of subscribers who actually opens your email and look forward to hearing from you week by week.

So, if you have a big list of people who really aren’t ever open your emails you run a higher risk of your emails being flagged as spam or getting high unsubscribe rates... And these are basically really bad signals to the email clients.

12. Segment your emails:

What happens if enough people mark your email as spam or unsubscribes, just because your content is not sufficiently targeted to their interest?

In this particular situation email clients can start putting you out of the inbox and into the promotions tab or even worse you can wind up in the junk folder.

And that goes for your entire list, including your contact who even like hearing from you, not just the ones who flagged you as a spammer.

Hint: What if you do not have any details of your subscribers? Use Link tagging and activity-based conditions in your email automation.

2. Your score with the subscriber’s behavior

Your subscribers’ behavior can be defined in 2 signals. Positive signals, and negative ones.

Positive signals:

Open: Subscribers frequently open your campaigns or even click the CTA in it. This keeps your emails landing the inbox.

Reply: If subscribers get in touch with you, (via reply email they send a response) to help improve your overall reputation with email providers.

Add to address book: When your subscribers add your email address to their address book. This shows that they care about receiving email from your domain and keep delivering them to the inbox.

Not spam: If recipients move your email out of the spam folder, or mark it as “not spam” is a very strong, positive signal. The email providers take this as a sign that campaigns are relevant and worthy of making the inbox.

Move to folder: When your emails are moved to various folders in the subscriber's inbox, it means that they care about your emails and are more likely to continue delivering them right to their inbox.

Negative Signals:

Move to junk: One of the strongest, negative signals. It means your email campaigns aren’t worthy to be delivered in inboxes.

Delete without open: After a quick look at the sender and subject line, your subscribers delete your campaign. It increases the risk for your future campaigns will be sent automatically to the spam box.

Other Factors:

  • Email volume through your domain.
  • Email Engagement and Sender Reputation (domain history): If your emails consistently have poor engagement, such as high bounce rates, filters may adapt to and it can result in your further emails going into the spam folder.
  • If the sender and the recipient email address are the same a warning message can be displayed above the email. (Use a different, personal email address for preview email sending)*
  • Corporate email domains have their own spam filters that can be more strict than the filters of free email clients.

*Let’s suppose the sender email address (you set in Automizy) is your own email address and you send the message to yourself.

It would give an impression that you've sent an email from your own email client. However, the email clients detect that the sending server is not its own, but an external server.

The test email is not the most appropriate form of email delivery testing.

e.g., the uniquely generated links (used to measure link clicks) don't work in preview emails. For example, the absence of an unsubscription link, manage preferences link increases the risk of being marked as spam. These links are required to include in any live email.

3. The reputation of the sending server IP addresses of your email software

The reputation of the sending server IP addresses of your email software is a third major factor to your email deliverability.

Just like motivating our users to protect their email address reputation, we do the same at Automizy.

We monitor our creditability on a daily routine, examine potential deliverability risks, and implement new technologies to maintain the efficiency of our servers and provide them in the best mood.

Monitoring and review processes that work behind the scenes to protect the reputation of the email sending infrastructure enables our customers to have an industry-leading delivery rate.

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